The selection of filtering your library feels sparse, you're only able to really sort by recently played, with filters matching title or a list of what's installed.

I'd like to see being able to sort and filter multiple ways, allowing for mix and match. Sorting = changing the order of the library, Filtering = only displaying games with a specified trait.

Sort by genre like the store, sort by date purchased, sort by date published, sort by metascore, sort by time played.

Filter games by genre, Filter owned games with any of the status symbols listed in the store (instantly list owned localy multiplayer games, for example), Filter out games played longer than x, filter by a tag (once that system isn't a total mess). and so on.

I'd like to be able to sort by date purchased and date installed. I often buy games when they're on sale and play them weeks or even months later. It would be nice to be able to sort my list to show me what I've purchased recently so I can decide what to play next.

I agree 100% with the OP. I have over 400 games in my library and it is difficult to find something new to play. If I could sort my library with some of the same categories available in the store it would be helpful. Even being able to filter by public tags would help. I would like to see something like this for both the desktop client as well as in big picture mode. My list is to long and it makes my eyes bleed.